I dropped my watch in the air vent system and don't know how to get it out.

You may have to go in from the bottom depending on where you dropped it you may be able to remove just a few panels or a vent duct to get to it. If you look under dash near the vent where it dropped you will notice that it has a vent duct that tuns into the heater box or the blower motor box. You may have to remove part of either box to get to the duct, it may have fallen all the way in anyway, before you can pull the duct out of its seat. It will simply pull straignt out but you may have to give it room to move on the end you are moving it towards. It is pretty easy to judge what screws or clips to remove to get to the area you want. So, try to find the passage it dropped in and track it's path to the bottom where it could fall no further. You may have to start there.